Spring mechanism in a shoe

ABSTRACT

A shoe can include a sole, a cavity defined in the sole, and a spring plate disposed within the cavity. The spring plate can include an elongated shape with a central axis where the central axis is aligned with length of the sole and a flat profile in the midfoot region of the sole.

BACKGROUND

Athletic shoes can be used in variety of circumstances and for a variety of purposes. Depending on the intended use of a shoe, it can be constructed differently or include different components than other types of shoes.

Running shoes can be constructed for multiple types of running environments and types of running. Often, road running shoes are constructed for running on pavement and other surfaces that are generally flat. These types of running shoes tend to be lightweight and flexible. Additionally, they include insulation to cushion or stabilize feet during repetitive strides on hard, even surfaces.

Cross-training shoes are constructed for workouts that include both aerobic and anaerobic types of activities. The soles of these shoes are often configured to maintain more contact with the ground to provide stability.

Trail-running shoes are often constructed for off-road routes that are rugged where the runner can encounter various obstacles such as puddles, mud, rocks, roots, and so forth. These shoes conventionally include aggressive treads for improved traction and are fortified to add stability and support. Generally, the outsole of the shoe extends substantially beyond the edges of the shoe's upper to provide the additional stability.

Sometimes, trail-running shoes will include what is referred to as a rock plate or a stone guard. The stone guard is a thin layer, often of plastic, that can be positioned adjacent the midsole and provides protection to the foot from abrupt protrusions or just in the running surface such as rocks or roots. These protrusions have been known to bruise or otherwise injure a runner's foot. Stone guards can provide a level of protection against such potential injuries. However, stone guards also tend to make the shoe substantially stiffer, which can result in discomfort or fatigue for the runner.

One example of a running shoe is disclosed in U.S. Pat. No. 8,312,647 issued to Theodor Hofmann on 20 Nov. 2012. The reference relates to a shoe, particularly to a sports shoe, with a sole where the sole includes at least one spring element that increases the bending stiffness of the sole around an axis which is oriented horizontally and perpendicular to a longitudinal direction of the sole. To create a shoe with a sole that has a sufficient bending stiffness and spring properties respectively without employing separate measures, i. e. without employing a spring element, the reference proposes that the sole includes at least one receiving groove for the at least one spring element, in which the spring element is arranged in such a manner that it can slide at least along a part of its extension in longitudinal direction relatively to the sole.

Another example of a running shoe is disclosed in U.S. Pat. No. 5,052,130 issued to Daniel T. Barry on 1 Oct. 1991. The reference discloses an athletic shoe with a spring plate in combination with a viscoelastic midsole, such spring plate extending substantially the length of the midsole from the medial side of the heel through the arch where the spring plate is curvilinear and on the exterior of the shoe, through the metatarsal head area and beneath the toes. The spring plate is of multiple layers, each of parallel carbon fibers embedded in polymer, the fibers being at acute angles in successive layers, in symmetry. The stiffness of the plate is anisotropic, being greater longitudinally than laterally. The thickness of the plate forward of the metatarsal break line is half that of the plate rearwardly of the break line.

Each of these references are herein incorporated by reference for all that they contain.

SUMMARY

In one embodiment, a shoe includes a sole, a cavity defined in the sole, and a spring plate disposed within the cavity. The spring plate includes an elongated shape with a central axis, the central axis being aligned with length of the sole, and a flat profile in the midfoot region of the sole.

The sole can include an outsole where the cavity is defined in the outsole.

The cavity can be open to an exterior of the outsole.

The spring plate can be adhered to the cavity with an adhesive.

The shoe can include a covered portion of the spring plate that is covered with the outsole and an exposed portion of the spring plate that is exposed through the outsole.

The spring plate can include a characteristic of flexing into a bended orientation under a load when worn by a user during an ambulatory foot movement and returning to a flat profile in an absence of a load.

The cavity can be defined in a midfoot region of the sole.

The spring plate can include a plate width that is transverse the central axis where the sole includes a sole width in a midfoot region of the sole and the plate width is a less than a third of the sole width.

The spring plate can include a plate length aligned with the central axis where the sole includes a sole length and the plate length is less than half of the sole length.

The plate length can be less than a third of the sole length.

The spring plate can have a flat profile.

The spring plate can be flat and have a uniform thickness.

The spring plate can be isolated to the midfoot region of the sole.

In one embodiment, a running shoe includes a sole, an upper connected to the sole, an inside surface of the upper defining a foot cavity with the sole, the sole includes an outsole, a cavity defined in the outsole, and a spring plate disposed within the cavity. The spring plate can include an elongated shape with a central axis and the central axis being aligned with length of the sole. The cavity can be open to an exterior of the outsole.

The spring plate can have a flat profile in the midfoot region of the sole.

The spring plate can include a characteristic of flexing into a bended orientation under a load when worn by a user during an ambulatory foot movement and returning to a flat profile in an absence of a load.

The spring plate can be flat and have a uniform thickness.

The spring plate can include a plate width that is transverse the central axis where the sole includes a sole width in a midfoot region of the sole and where the plate width is less than a third of the sole width.

The spring plate can include a plate length aligned with the central axis where the sole includes a sole length and where the plate length is less than half of the sole length.

In one embodiment, a running shoe includes a sole, an upper connected to the sole, an inside surface of the upper defining a foot cavity with the sole, the sole includes an outsole, a cavity defined in the outsole, and a spring plate disposed within the cavity. The spring plate can include an elongated shape with a central axis, a flat profile in the midfoot region of the sole, the central axis being aligned with length of the sole, a characteristic of flexing into a bended orientation under a load when worn by a user during an ambulatory foot movement and returning to a flat profile in an absence of a load, a uniform thickness, a plate width that is transverse the central axis where the sole includes a sole width in a midfoot region of the sole and where the plate width is a less than a third of the sole width, and a plate length aligned with the central axis where the sole includes a sole length and where the plate length is less than half of the sole length. The cavity can be open to an exterior of the outsole.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various embodiments of the present apparatus and are a part of the specification. The illustrated embodiments are merely examples of the present apparatus and do not limit the scope thereof.

FIG. 1 illustrates a side view of an example of a shoe in accordance with the present disclosure.

FIG. 2 illustrates an exploded view showing various components associated with the sole of a shoe in accordance with the present disclosure.

FIG. 3 illustrates a bottom view of an example of a shoe in accordance with the present disclosure.

FIG. 4 illustrates a cross-sectional side view of an example of an outsole in accordance with the present disclosure.

FIG. 5 illustrates a cross-sectional side view of an example of an outsole in accordance with the present disclosure.

FIG. 6 illustrates an exploded view of an example of an shoe in accordance with the present disclosure.

FIG. 7 illustrates an exploded view of an example of an shoe accordance with the present disclosure.

DETAILED DESCRIPTION

For purposes of this disclosure, the term “aligned” means parallel, substantially parallel, or forming an angle of less than 35.0 degrees. For purposes of this disclosure, the term “transverse” means perpendicular, substantially perpendicular, or forming an angle between 55.0 and 125.0 degrees. Also, for purposes of this disclosure, the term “length” means the longest dimension of an object. Additionally, for purposes of this disclosure, the term “width” means the dimension of an object from side to side. Often, the width of an object is transverse the object's length.

For the purposes of this disclosure, the term “ambulatory” generally refers to movements associated with walking, running, or similar exercises. Often, an ambulatory movement includes the foot's position as it strikes a surface, and the movement of rolling the foot towards the user's toe, and the process of launching the foot off of the surface at the forefront of the foot. In some cases, the foot can strike the surface at the heel, midfoot region, forefront portion, or another portion of the foot.

FIG. 1 depicts an example of a running shoe 100. In this example, the running shoe 100 includes a sole 102 and an upper 104 connected to the sole 102. The sole 102 and the upper 104 collectively define a foot cavity 106 that receives a foot of the user. The upper 104 includes a slit or an opening 108 that enables the size of the foot cavity 106 to vary while the user inserts or removes their foot. A tongue 110 is connected to the upper 104 near the end of the slit 108. The tongue 110 fills the gap defined by the slit 108 when the user is wearing the running shoe 100. Multiple eyelets 112 are defined in the upper 104 adjacent to the slit 108 through which a lace passes in a desired lacing pattern. The lace can be loosened to enable the foot cavity to be expanded while a user inserts or removes their foot, and can be tightened when the running shoe 100 is worn by the user to secure the user's foot within the foot cavity 106 of the shoe 100.

The foot cavity 106 can include a sock liner that lines portions of the foot cavity 106. Also, the side walls of the foot cavity 106 can include other types of cushioning that reduce the jarring impacts when the user's shoe strikes the running surface and holds the upper snuggly against the user's feet throughout the running motion. In some cases, the cushioning lines the entire surface of the foot cavity's wall. In other examples, the cushioning lines just a subset of the foot cavity 106.

In the example depicted in FIG. 1, the running shoe's upper 104 is configured as a low top profile wherein the upper 104 terminates at or below the user's ankle. The low top profile 116 provides the running shoe with a lower weight and provides the user additional movement.

Referring to FIG. 2, an exploded view of the sole 102 of the shoe 100 depicted in FIG. 1 is illustrated according to one example. The sole 102 includes an outsole 120 having a desired tread or pattern on its lowermost surface for engagement with a running surface. In the embodiment shown, the tread includes a variety of lugs 122 or other protrusions in what might be considered an aggressive pattern used for trail-running. The outsole can additionally include a toe bumper or toe guard 124 providing some protection for the user's toes as well as providing an ergonomic traction surface associated with a runner rolling up onto and pushing off of their toes while they run.

The sole 102 additionally includes a midsole 130 positioned about the outsole 120. The midsole 130 is configured to provide cushioning and shock absorbing to the runner. In one embodiment, the midsole can be formed of ethyl vinyl acetate (EVA).

A spring plate 160 is incorporated into the sole 102. In this example, the spring plate 160 is positioned between the outsole 120 and the midsole 130. The spring plate 160 can assist the shoe in rebounding during an ambulatory movement.

FIG. 3 depicts a view of an example of an underside of a shoe 100. In this example, the outsole 120 is depicted. A cavity 170 is defined in a midfoot region 175 of the outsole 120, and a spring plate 160 is disposed within the cavity 170.

In this example, the spring plate 160 includes an elongated shape with a flat profile. The spring plate 160 includes a central axis 172 that is aligned with a length 174 of the outsole 120 of the shoe 100. In the illustrated example, the spring plate 160 includes a length 176 that is less than a third of the length 174 of the outsole 120. Further, the width 178 of the spring plate 160 is less than a third of the width 182 of the outsole when measuring the outsole's width at its narrowest section 180. In this example, the spring plate 160 is not in the forefoot region 184 or the heel region 186 of the outsole 120. The cavity 170 and the spring plate 160 are located in a central region 188 of the midfoot region 175.

In some cases, the medial adjacent region 190 to the cavity 170 is at least as wide as the cavity 170. In some cases, the medial adjacent region 190 to the cavity 170 is at least as wide as the spring plate 160. In some cases, the lateral adjacent region 192 to the cavity 170 is at least as wide as the cavity 170. In some cases, the lateral adjacent region 192 to the cavity 170 is at least as wide as the spring plate 160.

FIG. 4 depicts a side view of the outsole 120. In this example, the cross-section cut falls through the spring plate 160. The cavity 170 into which the spring plate 160 is disposed, extends from a top surface 194 of the outsole 120 to a bottom surface 196 of the outsole. In the illustrated example, the spring plate 160 is disposed in a section of the cavity 170 that is adjacent to the top surface 194. The spring plate 160 closes off the cavity 170. The outsole 120 covers a peripheral region 198 of the spring plate 160, and a central region 200 of the spring plate 160 is exposed through the bottom surface 196.

FIG. 5 depicts a front view of the outsole 120. In this example, the cross-section cut falls through the spring plate 160. The cavity 170 includes a recess 202 defined in the top surface 194 of the outsole 120 and the spring plate is nested within the recess 202 so that the spring plate 160 is flush with the top surface 194. The cavity 170 includes a neck 204 that leads from the recess 202 to an outward taper 206.

FIGS. 6 and 7 depict an example of a shoe 600. In this example, the shoe 600 includes an upper 602, a sole 604, and a spring plate 606 disposed between the upper 602 and the sole 604. A midsole 608 and an outsole 610 are depicted in the illustrated example. The spring plate 606 includes a width that approximately the width of the shoe in the forefront portion 612 of the upper 602. The spring plate 606 narrows with respect to the upper 602 in the upper's heel portion 614. The midsole 608 includes a plurality of grooves 616 defined in the top surface of the midsole 608 that gives the midsole 608 greater flexibility. In some cases, the spring plate 606 may cover all the grooves 616.

General Description

In general, the present disclosure provides users with a shoe that includes a spring plate to assist the user during ambulatory movements. The spring plate can be disposed in a cavity that is defined in the outsole of the shoe. In some examples, the spring plate is positioned just in the midfoot region of the sole. The length of the spring plate can be a third or less than a length of the entire outsole. In some cases, the width of the spring plate is a third or less than a width of the outsole at the narrowest width of the outsole.

In some embodiments, the outsole can include a rubber compound with a high carbon content at the heel and in the toe box area. The outsole can be constructed with studs, ridges, or other tread structures to provide traction on slippery surfaces, such as wet grass or slick pavement. In some examples, the outsole can include transverse grooves in the toe box area so that the running shoe is more flexible in the toe box area when the user's weight is loaded against the ball of the user's foot while the heel is raised off of the ground. Generally, the wider the outsole, the greater stability the outsole provides the foot. Although, a wide outsole can also increase the weight of the shoe. In some examples, the running shoe can include an outsole that is just as wide or has a width that is less than 5.0 percent greater than width of other corresponding sections of the shoe (e.g., corresponding sections of the midsole or upper).

The midsole of the sole is located above the outsole. The midsole is made of a material that provides cushioning while also providing stability. In some embodiments, the total height of the midsole and outsole under the heel can be about 1.0 inch and the total height of the midsole and outsole under the toe box can be about 0.6 inches. The difference in sole thickness between the heel and toe box can reduce the strain on the user's Achilles tendon. This drop in the height of the sole from the heel to the toe box can affect how the user's foot strikes the ground. In some cases, the heel drop can range from 4 mm to 10 mm.

The midsole can be constructed of various materials to provide cushioning. In some cases, the midsole is made of ethyl vinyl acetate (EVA) or polyurethane. EVA is a copolymer of ethylene and vinyl acetate with microscopic air bubbles formed within the material making it lightweight while providing a good amount of cushioning. Polyurethane also has a microscopic air bubble structure like EVA but is generally firmer and more resistant to compression than EVA.

The shoe can further include an upper attached to the sole. In some embodiments, the upper can be made of a combination of lightweight nylon to reduce the running shoe's weight. However, a variety of other materials can be used to form the upper. The upper of a running shoe can also incorporate a heel counter that is commonly stiffer than in other athletic shoes to help control excessive pronation or supination during running.

In some embodiments, the upper can be formed of waterproof fabric. This prevents water from entering the shoe through the upper. The tongue of the running shoe can also include a waterproof fabric. In some circumstances the waterproof fabric of the tongue has the same characteristics as the waterproof fabric incorporated into the upper. In some embodiments, the waterproof fabric can be located on the underside of the tongue and on the inside of the upper adjacent the foot cavity. In some embodiments, the waterproof fabric of the upper that is located on the outside of the upper. In some embodiments, the tongue can be connected to the upper along the tongue's edges with a gusset. The gusset can also be lined with the waterproof material. In some cases, the gusset's waterproof fabric is located on the inside surface that is adjacent to the foot cavity. In other examples, the gusset's waterproof fabric is located on the outside surface of the gusset.

In some cases, the waterproof fabric is small enough to exclude water particles that would come from the ambient environment such as water from rain, mud puddles, or other sources while enabling water to move from the inside of the shoe to the outside through a diffusive mechanism. The diffusive water transport mechanism allows some water to be removed from the inside of the running shoe or from the inside layers of the running shoe.

The waterproof fabric that forms the protective exterior also includes a second, convective water transport mechanism. The convective water transport mechanism is enabled due to the waterproof fabric being air permeable such that a small amount of air passes through the waterproof fabric. This additional air circulation accelerates the removal of water moisture inside the foot cavity or water moisture inside the upper's insulation in the inside layer. Convective mass transport works largely via advection or the transport of water through air motion. The convective mass transfer does not require sweat build up. The waterproof fabric can transport air out of the shoe when the user's foot is inserted into the shoe or not.

Any appropriate type of running shoe, trail-running shoe, or cross-training shoe can be used in accordance with the principles described herein. In one example, the shoe can include a low-top profile where the upper terminates just below the user's ankle. While a low-top upper can provide less lateral stability, the shoe is lighter. In other examples, the shoe includes a high-top profile. In this example, the running shoe includes an upper that extends over the user's ankle. Other types of shoes, including non-athletic shoes, can also incorporate the principles, features or aspects disclosed herein.

The spring plate can be incorporated into the sole of the shoe in any appropriate arrangement. In some cases, the spring plate is incorporated in the outsole, the midsole, or combinations thereof. In one particular example, the spring plate can be disposed at a junction of the outsole and the midsole. In this example, a top surface of the spring plate can be in contact with the midsole, and a bottom surface of the spring plate can be in contact with the outsole. In one case, the spring plate can compress materials of the outsole and midsole to be disposed at their junction. In yet another example, a cavity can be defined in the outsole, the midsole, or both. In one case, a cutout or recess defined in the bottom surface of the midsole can provide a location for the spring plate. In other examples, a cutout or recess defined in a top surface of the outsole can provide a location for the spring plate. In some examples, a first recess can be defined in the outsole and a second recess can be defined in the midsole, and the spring plate can be partially disposed in the recesses of the midsole and the outsole. In yet another example, the midsole, the outsole, or other portions of the sole can be formed around the spring plate. For example, the outsole can be injection molded around the spring plate so that the spring plate is surrounded on a top side and a bottom side by the material of the outsole. Likewise, in another example, the midsole can be formed around the spring plate so that a top side and a bottom side of the spring plate are covered by the materials of the mid-sole.

The recess of the outsole and/or the recess of the midsole can be created by molding the outsole and/or midsole around the spring plate in a co-molding process. By co-molding the midsole and/or the outsole with the spring plate, no gaps, voids, or irregularities can be present between the materials of the outsole/midsole and the spring plate.

Further, the spring plate can be glued or otherwise adhered to the recess with an adhesive. The adhesive prevents the spring plate from sliding within the recesses and/or cavity of the sole. In conjunction with the walls of the recess and the adhesive, the spring plate can be locked in place within the sole. By having a spring plate that cannot slip out of place, the sole is buttressed to support all loads when the user is wearing the shoe. In those examples, where the spring plate is positioned in the sole during the manufacturing process of the sole, a user cannot take the spring plate out of the sole without destructively manipulating the sole. In these examples, this ensures that the user does not take the spring plate out. With the adhesive and recess walls in place, the spring plate cannot slip in a direction that is aligned with the central axis of the spring plate. Also, with the adhesive and recess walls in place, the spring plate cannot slip in a direction that is transverse to the central axis of the spring plate.

In some examples, the recess is defined in a top surface of the outsole and is part of a cavity that connects the top surface of the outsole to the bottom surface of the outsole, which engages the ground when the shoe is worn by the user and the user performs an ambulatory movement. The cavity can include a neck that opens into the recess at the top surface of the outsole. The neck can also open into a tapering region at the bottom surface of the outsole. In some examples, the neck has a narrower width than the width of the spring plate. Further, the neck can have a length that is narrower than the length of the spring plate. In some cases, the outsole can cover a peripheral portion of the spring plate while a central portion of the spring plate is exposed in the cavity since it located by the neck of the cavity. In this example, a central region of the spring plate is visible from the bottom surface of the midsole. In some examples, the tapered region defined in the bottom surface of the outsole is as wide as the spring plate is wide. In some examples, the tapered region defined in the bottom surface of the outsole is as long as the spring plate is long.

The tapered region of the bottom surface can work collectively with the spring plate to provide a desired tension in the sole. With a portion of the midsole being absent adjacent to the central region of the spring plate, the outsole does not affect the spring tension of the sole in this region of the outsole. Further, the portion of the spring plate that is covered with the outsole has a smaller thickness than the other portions of the outsole. As a result, the tension provided by the spring plate in the spring plate's peripheral portion has a lower effect on the spring plate than the outsole would have if the outsole had the same thickness at the peripheral portion as it has in the other regions of the outsole, such as in the toe region, forefoot region, and heel regions. Thus, the location, depth, and geometry of the cavity work together with the spring plate to provide a desired amount of spring tension in the sole of the shoe.

The spring plate can include any appropriate shape. In some examples, the spring plate has an elongated shape where the length of the spring plate is at least two to three times longer than the width or thickness of the spring plate. In some cases, the length of the spring plate is at least four to five times longer than the width or thickness of the spring plate. The elongated shape of the spring plate can include a central axis that is aligned with the length of the sole of the shoe.

In some cases, the width of the spring can be a third or less than a width of the sole of the shoe, even at the narrowest portion of the sole. This narrower length prevents the sides of the spring plate from substantially affecting the pronation of the user's foot. In some cases, the angle of the spring plate's central axis can be tilted to affect the pronation of the user's foot. However, in some examples, the spring plate's narrower shape provides the advantage of minimally affecting the pronation of the user's foot while still providing the desired spring to assist the user with an ambulatory movement.

In some cases, the length of the spring plate can be a third or less than a length of the sole of the shoe. This length can prevent the spring plate from entering into the forefoot or heel regions of the sole of the shoe thereby isolating the physical presence of the spring plate to the midfoot region of the sole.

In some examples, the spring plate includes a shape that matches or closely matches the profile of the insole of the shoe. This may include the spring plate having substantially the same length and the insole, having substantially the same width as the insole, or combinations thereof. In some embodiments, the spring plate may have a width that is approximately the same width as a the insole at the narrowest portion of the insole, at the widest portion of the insole, at another portion of the insole, or combinations thereof. In some cases, the spring plate may have approximately the same width as the insole in the forefront region of the insole, while the spring plate is narrower than the insole in the shoe's heel portion.

The ball of the user's foot can correspond to the forefront of the shoe's sole, and the ball of the user's foot is where an immense amount of pressure is applied when the user is performing an ambulatory movement. Due to the high amount of pressure that is loaded to this portion of the foot from walking, running, or other types of exercises, many users experience pain in the balls of their feet. By keeping the forefoot region of the sole free of the spring plate, the forefoot region of the sole can be dedicated to padding. Further, by keeping the spring plate out of the forefoot region of the sole, the spring plate avoids receiving high bending loads that can otherwise necessitate a more robust construction of the spring plate.

The heel of the foot generally acts as a landing area that distributes the loads of the user's body weight when the user's foot strikes a surface. By keeping the spring plate out of the heel region of the sole, the sole's heel region can be dedicated to padding and other materials that distribute the user's load over a wider area.

The spring plate can include a uniform length, a uniform thickness, a uniform width, or combinations thereof. The uniform dimensions can provide a flat profile of the spring plate. At least one of these uniform dimensions can provide a constant spring coefficient throughout the spring plate. In some examples, at least one side of the spring plate has a rectangular shape. In other examples, at least one side of the spring plate can include an oval shape, an asymmetric shape, another type of shape, or combinations thereof.

In one example, the spring plate has a flat profile in the midfoot region of the sole. In midfoot region of the sole can correspond to the portion of the sole that is adjacent to the arch of the user's foot. In this regions of the sole, the sole can conform to the shape of the arch to provide the user support at the arch. In this example, the flat profile of the spring cannot bend with the contour of the user's foot to provide support to the arch, but the spring plate can provide the spring tension in the midfoot region that assists the arch when pushing off of the surface during an ambulatory movement.

In some cases, the spring plate is located in just the midfoot region of the sole. In such an example, the toe region, the forefoot region, and the heel region of the sole are free from the presence of the spring plate. However, even in those examples where these portions of the sole are free from the presence of the spring plate, the spring tension provided by the spring plate can affect the tension in these portions of the sole.

The spring plate can be made of any appropriate type of materials. A non-exhaustive list of materials that can be used in the spring plate include, but are not limited to, a metal, a steel, a stainless steel, a polymer, a plastic, a carbon fiber, another type of fiber, another type of material, or combinations thereof.

In some examples, the spring plate is made of a curable material. For example, a pre-pregnated material, such as a carbon fiber, a fiberglass, or another type of material may be used to assemble the spring plate into the sole. During a pre-curing stage, the pre-pregnated material may be flexible and easy to fit into the recess or other type of cavity in the sole. In some cases, the pre-pregnated material may be placed on a surface of the midsole or another surface of in the sole. After assembly, the sole of the shoe may be cured, which causes the pre-pregnated material to stiffen to have the spring-like characteristic described above. The spring plate may be cured with an increased temperature. However, in some examples, other forms of energy may be used to cure the spring plate. For example, ultraviolet light, blue light, another type of light, heat, other forms of radiation, or combinations thereof may be used to cure the spring plate.

During an ambulatory movement when a user is wearing the shoe, the user's foot can strike the ground on the heel region of the sole with the forefoot region of the sole being at a higher elevation than the heel region. The user's foot can pivot on the heel region so that the forefoot region comes into contact with the ground. As the user moves forward, the load on the heel region of the sole is transferred to the forefoot region of the sole as the user's weight transitions from the user's heel to the ball of the user's foot. With the weight of the user loaded to the ball of the foot, the user pushes off the ground at the ball of the foot creating a propulsion force to propel the user in a forward direction.

The spring plate is affected during the ambulatory process. With no loads on the spring plate, the spring plate retains a substantially flat profile. In some cases, as the weight of the user is transferred to the ball of the user's foot, the spring plate bends from its flat profile building up a spring tension that urges the spring plate to return to the flat profile. As the user pushes off the ground with the ball of the foot, the spring plate continues to urge the spring plate to return to its flat profile. The energy exerted by the spring plate to return to the flat profile constructively adds to the forces provided by the user to propel himself or herself forward. As a result, the user is propelled forward by a greater amount than the user would have otherwise been propelled without the assistances of the spring plate.

In some cases when the spring plate is not located in the forefoot region of the sole, the forefoot region of the sole is still influenced by the spring tension generated with the spring plate. As the user performs the ambulatory movement, the midfoot region of the sole bends, and the spring plate assists in straightening out the midfoot region as the user pushes off the ground.

In some cases, the midsole includes at least one groove that is defined in the top surface of the midsole. The groove may be aligned with a length of the shoe, be transversely oriented with respect to the shoe, be angled with respect to the length and/or width of the shoe, or combinations thereof. In some cases, the midsole includes a plurality of grooves defined in the midsole's top surface. The spring plate may cover at least one of the grooves, a subset of the groove, or all of the grooves. With the spring plate covering the grooves, the grooves and the spring plate may collectively define a tunnel. In those examples where a plurality of grooves define in the top surface of the midsole intersect with each other and the spring plate covers at least a portion of the grooves, the spring plate and the grooves may defined a network of interconnected tunnels.

While the spring plate has been described herein with specific dimensions and shapes, any appropriate dimensions and shapes can be used in accordance with the principles described herein. While the spring plate has been described herein with a specific location and orientation, any appropriate location and orientation can be used in accordance with the principles described herein. While the shoe has been described herein with specific configurations, any appropriate configuration can be used in accordance with the principles described herein. 

What is claimed is:
 1. A shoe, comprising: a sole; a cavity defined in the sole; a spring plate disposed within the cavity, the spring plate including: an elongated shape with a central axis; the central axis being aligned with length of the sole; and a flat profile in a midfoot region of the sole.
 2. The shoe of claim 1, wherein the sole includes an outsole, wherein the cavity is defined in the outsole.
 3. The shoe of claim 2, wherein the cavity is open to an exterior of the outsole.
 4. The shoe of claim 3, wherein the spring plate is adhered to the cavity with an adhesive.
 5. The shoe of claim 3, wherein a covered portion of the spring plate is covered with the outsole and an exposed portion of the spring plate is exposed through the outsole.
 6. The shoe of claim 1, wherein the spring plate includes a characteristic of flexing into a bended orientation under a load when worn by a user during an ambulatory foot movement and returning to the flat profile in an absence of the load.
 7. The shoe of claim 1, wherein the cavity is defined in the midfoot region of the sole.
 8. The shoe of claim 1, wherein: the spring plate includes a plate width that is transverse the central axis; the sole includes a sole width in the midfoot region of the sole; and the plate width is a less than a third of the sole width.
 9. The shoe of claim 1, wherein: the spring plate includes a plate length aligned with the central axis; the sole includes a sole length; and the plate length is less than half of the sole length.
 10. The shoe of claim 9, wherein the plate length is less than a third of the sole length.
 11. The shoe of claim 1, wherein the spring plate has an overall profile that is flat.
 12. The shoe of claim 1, wherein the spring plate comprises a pre-pregnated composite material.
 13. The shoe of claim 1, wherein the spring plate is isolated to the midfoot region of the sole.
 14. A running shoe, comprising: a sole including an outsole; an upper connected to the sole; an inside surface of the upper defining a foot cavity with the sole; a cavity defined in the outsole; a spring plate disposed within the cavity, the spring plate including: an elongated shape with a central axis; and the central axis being aligned with length of the sole; wherein the cavity is open to an exterior of the outsole.
 15. The running shoe of claim 14, wherein the spring plate has a flat profile in a midfoot region of the sole.
 16. The running shoe of claim 14, wherein the spring plate includes a characteristic of flexing into a bended orientation under a load when worn by a user during an ambulatory foot movement and returning to a flat profile in an absence of the load.
 17. The running shoe of claim 14, wherein the spring plate is flat and has a uniform thickness.
 18. The running shoe of claim 14, wherein the spring plate includes a plate width that is transverse the central axis; wherein the sole includes a sole width in a midfoot region of the sole; and wherein the plate width is a less than a third of the sole width.
 19. The running shoe of claim 14, wherein the spring plate includes a plate length aligned with the central axis; the sole includes a sole length; and the plate length is less than half of the sole length.
 20. A running shoe, comprising: a sole including an outsole; an upper connected to the sole; an inside surface of the upper defining a foot cavity with the sole; a cavity defined in the outsole; a spring plate disposed within the cavity, the spring plate including: an elongated shape with a central axis; a flat profile in a midfoot region of the sole; the central axis being aligned with length of the sole; a characteristic of flexing into a bended orientation under a load when worn by a user during an ambulatory foot movement and returning to the flat profile in an absence of the load; a uniform thickness; a plate width that is transverse the central axis; wherein the sole includes a sole width in the midfoot region of the sole; wherein the plate width is a less than a third of the sole width; a plate length aligned with the central axis; wherein the sole includes a sole length; wherein the plate length is less than half of the sole length; and wherein the cavity is open to an exterior of the outsole. 